Goethe considered his own theory to be a more general explanation of colour, with Isaac Newton's observations being special cases[1]. Goethe's work was not well accepted by the physics community of his day and is not typically discussed in modern accounts of the history of science. Physicists have come to understand, however, the distinction between the optical spectrum, as observed by Newton, and the phenomenon of human perception of colour. Developments in understanding how the brain interprets colours, for example colour constancy and Edwin Land's retinex theory, bear striking similarities to Goethe's theory of colours—particularly his focus on brightness and contrast as the determining factors of colour perception.

When the eye sees a colour it is immediately excited, and it is its nature, spontaneously and of necessity, at once to produce another, which with the original colour comprehends the whole chromatic scale. A single colour excites, by a specific sensation, the tendency to universality. In this resides the fundamental law of all harmony of colours...

—Goethe, Theory of Colours, p. 317

Theory of Colours not only parted radically with the dominant Newtonian light and optical theories of his time, but also with the entire Enlightenmentmethodology of reductive science. Although the theory was not received well by scientists, Goethe – considered one of the most important intellectual figures in modern Europe – thought of his colour theory as his greatest accomplishment. Holistic theorists and scientists such as Rupert Sheldrake still refer to Goethe's Theory of Colours as an inspiring example of holistic science. The introduction to the book lays out Goethe's unique philosophy of science.

Contents

In the 1780s, Goethe was asked to return a prism which had been on loan from the Privy Councillor Buettner in Jena. As he was returning it, he paused to take a look through -- and what he saw led him to a comprehensive study of light phenomenon, culminating in The Theory of Colours.

Along with the rest of the world I was convinced that all the colours

are contained in the light; no one had ever told me anything different,

and I had never found the least cause to doubt it, because I had

no further interest in the subject. (Goethe)

At the time, it was already popularly believed that the prismatic phenomenon is a process of splitting up the colourless light into the colours. Newton's theory stated that colourless light already contains the seven colours within itself—and when we channel this light through a prism, the prism does no more than to fan out and separate what is already there in the light—the seven colours, into which it is thus analyzed.

Goethe reasoned: In such way the phenomena are interpreted, but this is not the primal or complete phenomenon. A look through the prism shows that we do not see white areas split evenly into seven colours. Rather, we see colours at some edge or border-line.

If we let a cylinder of colourless light impinge on the screen, it shows a colourless picture. Putting a prism in the way of the cylinder of light, we get the sequence of colours: red, orange, yellow, green, cyan, blue, violet.

Figure I

If we let light pass through the space of the room, we get a white circle on a screen. Put a prism in the way, and the cylinder of light is diverted (Figure I), but what appears is not the series of seven colours at all, only a reddish colour fanning out from the upper edge, passing over into yellow, and on the lower edge a blue passing over into greenish shades. In the middle it stays white.

Goethe now said to himself: It is not that the light is split up or that anything is separated out of the light as such. In point of fact, I am projecting a picture—simply an image of this circular aperture. The aperture has edges, and where the colours occur the reason is not that they are drawn out of the light, as though the light had been split up into them. It is because this picture which I am projecting—the picture as such—has edges. Here too the fact is that where light adjoins dark, colours appear at the edges. It is none other than that. For there is darkness outside this circular patch of light, while it is relatively light within it.

The colours therefore, to begin with, make their appearance purely and simply as phenomena at the border between light and dark. This is the original, the primary phenomenon. We are no longer seeing the original phenomenon when by reducing the circle in size we get a continuous sequence of colours. The latter phenomenon only arises when we take so small a circle that the colours extend inward from the edges to the middle. They then overlap in the middle and form what we call a continuous spectrum, while with the larger circle the colours formed at the edges stay as they are. This is the primal phenomenon. Colours arise at the borders, where light and dark flow together. The prism serves only to shift light and dark over each other.

The spectrum, therefore, is a compound phenomenon. In the familiar prismatic experiment, you get colour at the edges, and where the red-yellow and blue-violet edges meet, you get green.

Because the colour phenomenon relies on the adjacency of light and dark, there are therefore two ways to produce a spectrum: with a light beam surrounded by dark, and with a dark beam surrounded by light, as illustrated below.

From the Newtonian standpoint, darkness is an absence of light. According to this view, the light which streams into a dark space has no resistance from the darkness to overcome.

Goethe pictures to himself that light and darkness relate to each other like the north and south poles of a magnet. The darkness can weaken the light in its working power. Conversely, the light can limit the energy of the darkness. In both cases colour arises.

Today, Goethe's Theory of Colours is still remarkably accurate in its phenomenological observations. The Newtonian view sees darkness as an absence of light. All colours are contained within light only, and are split out according to their wavelengths. This is the basis for the usual understanding of light as a wave-particle duality where colour is regarded as the visible manifestation of its wavelength.

Goethe, on the other hand, saw light and dark related as the north and south poles of a magnet, and colour arises from their interplay. This reification of darkness has caused almost all of modern physics to reject Goethe's theory as unscientific. Yet Goethe was consistently more empirical in his approach. A modern physicist who actually reads the book would be hard pressed to find a single observation with which he could disagree.

"As Feigenbaum understood them, Goethe's ideas had more true science in them. They were hard and empirical. Over and over again, Goethe emphasized the repeatability of his experiments. It was the perception of colour, to Goethe, that was universal and objective. What scientific evidence was there for a definable real-world quality of redness independent of our perception?" (James Gleick, 'Chaos', William Heinemann, London, 1988, pp. 165-7)

Goethe's experiments on light also more accurately depict the complexities of human colour perception. Goethe's emphasis on brightness and boundaries correlates with modern research on the perception of colour [2]; while Goethe's idea of colour constancy correlates with Edwin Land's Retinex theory.

Where Newton's studies were aimed more towards the development of a mathematical explanation for the behaviour of light, Goethe was focused on exploring how colour is perceived in a complex array of conditions.

[Goethe] delivered in full measure what was promised by the title of his excellent work: data toward a theory of color. They are important, complete, and significant data, rich material for a future theory of color. He has not, however, undertaken to furnish the theory itself; hence, as he himself remarks and admits on page xxxix of the introduction, he has not furnished us with a real explanation of the essential nature of color, but really postulates it as a phenomenon, and merely tells us how it originates, not what it is.

Goethe's theory of the origin of the spectrum isn't a theory of its origin that has proved unsatisfactory; it is really not a theory at all. Nothing can be predicted by means of it. It is, rather, a vague schematic outline, of the sort we find in James's psychology. There is no experimentum crucis for Goethe's theory of colour.